JP2795173B2 - Nozzle device of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle device of an injection molding machine for injecting a molten resin into a mold.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show a nozzle apparatus of an injection molding machine. The nozzle device shown in FIG. 7 is for preventing resin leakage in an ordinary single-material injection molding machine. To explain this, the nozzle device is provided inside a nozzle 11 having an injection port 11a at the front end (the left side is the front in the figure). The needle 12 which is brought into contact with the inner side wall (valve seat) 11b of the injection port 11a to close the injection port 11a
The needle 12 is inserted into the piston rod 15b of the hydraulic cylinder 15 through a lever 14 which is inserted concentrically with the shaft 1 and movably in the axial direction, and is turned around a pin 13.
(See Japanese Utility Model Laid-Open No. 59-160216). The piston rod 15b is connected to the lever 14 by a pin 16.

FIG. 8 shows a nozzle device of an injection molding machine capable of simultaneously or separately injecting two or more types of resins having different types and colors into a single mold to perform sandwich molding or the like. . This nozzle device has an injection port 1 at the front end.
a, an inner nozzle 2 having an injection port 2a at the front end thereof and closing the outer nozzle 1 in contact with a valve seat 1b of the outer nozzle 1 connects an outer nozzle 1 with a flow chamber C1 communicating with the injection device 4. 1 and is inserted concentrically with the outer nozzle 1 and movably in the axial direction, and is inserted into the inner nozzle 2 so that the outlet 2a of the inner nozzle 2 has the same length as the outlet 2a. The needle 3 for closing the inner nozzle 2 by fitting the closing shaft 3a over the entire length thereof forms a flow chamber C2 communicating with the injection device 5 between the needle 3 and the inner nozzle 2 so as to be concentric with the inner nozzle 2 and in the axial direction. It is inserted movably.

The inner nozzle 2 is provided with a hydraulic cylinder 6 for axially moving the inner nozzle 2 with respect to the outer nozzle 1. The needle 3 is provided with the needle 3 in the axial direction. A hydraulic cylinder 7 is provided for moving the hydraulic cylinder 7.

[0005] The hydraulic cylinder 6 has a cylinder body 6a.
Are connected directly to the rear end of the outer nozzle 1 and the piston rod 6b is connected directly to the rear end of the inner nozzle 2. Also,
The hydraulic cylinder 7 has a cylinder body 7 a formed at the rear end of the inner nozzle 2, and a piston rod 7 b directly connected to the rear end of the needle 3. The injection device 4 communicates with the flow chamber C1 through the flow hole 1c formed in the outer nozzle 1 and the groove formed in the inner nozzle 2, and the injection device 5 is formed in the nozzles 1 and 2. The structure communicates with the flow chamber C2 through the flow holes 1d and 2d and the groove formed in the needle 3.

In the nozzle device, when the injection device 4 is operated to inject resin, the solenoid a of the solenoid valve 8 is excited and the inner nozzle 2 is retracted by the driving cylinder 6 to thereby cause the valve seat of the outer nozzle 1 to be retracted. The inner nozzle 2 is separated from the outer nozzle 1b, and the injection port 1a of the outer nozzle 1 is opened as shown in FIG.

When the resin is injected by the operation of the injection device 5, the solenoid a of the solenoid valve 8 is demagnetized and the inner nozzle 2 is advanced by the hydraulic cylinder 6 to abut the valve seat 1 b of the outer nozzle 1. Then, the outer nozzle 1 is closed, and the solenoid b of the solenoid valve 9 is excited to release the hydraulic cylinder 7.
The needle 3 is retracted to pull out the closing shaft 3a from the injection port 2a of the inner nozzle 2, and the injection port 2a of the inner nozzle 2 is opened (see Japanese Utility Model Laid-Open Publication No. 63-161811). Such a nozzle device is disclosed in JP-A-60-2123.
No. 15, Japanese Patent Publication No. Hei 4-84654, Japanese Patent Publication No. 55
No. 45374.

[0008]

The nozzle 11 shown in FIG.
Since the outer nozzle 1 in FIG. 8 is configured to be closed by contact of the needle 12 or the inner nozzle 2 with the valve seats 11b, 1b, the output of the cylinders 15, 6 acts on the valve seats 11b, 1b. And the valve seats 11b, 1b
Etc. are apt to be damaged. Cylinder 15, 6
If the output is reduced, the above point is reduced, but if the injection pressure of the resin is high, the injection ports 11a and 1a cannot be completely closed.

In the case of the inner nozzle 2 shown in FIG.
Since the closing shaft 3a is closed by fitting the closing shaft 3a into the opening 3, there is no such problem as long as the root of the closing shaft 3a of the needle 3 is not brought into contact with the inner side wall 2b of the injection port 2a. However, since the closing shaft 3a having the same length as the injection port 2a is fitted over the entire length of the injection shaft 2a to close the injection port 2a, there are the following problems.

Since a long opening / closing stroke of the closing shaft 3a is required, an operation delay is easily caused. After the pressure-holding step is completed and the resin in the cavity is solidified, the needle 3 is moved to close the injection port 2a. At this time, since the closing operation of the closing shaft 3a causes a large amount of resin to be extruded from the injection port 2a, A variety of troubles are likely to occur when the nozzle touch portion protrudes as a protrusion or is forcibly pushed into a runner or a sprue.

When the closing shaft 3a is pulled out from the injection port 2a, the resin pressure applied around the closing shaft 3a instantaneously becomes unbalanced due to the start of injection of the resin from the injection port 2a, so that the closing shaft 3a is bent. Works, but the closed shaft 3a
If the length is as described above, the bending may cause a breakage.

An object of the present invention is to provide a nozzle device of an injection molding machine which does not cause troubles such as operation delay and burrs, and which does not cause damage to a nozzle and a needle due to driving pressure or resin pressure.

[0013]

In order to achieve the above-mentioned object, the present invention provides a nozzle having a straight outlet at a front end thereof, the nozzle being fitted into the outlet and closing the outlet. A needle having a closed shaft formed at the front end is inserted concentrically with the nozzle and movably in the axial direction, and the needle is provided with a driving device for moving the needle in the axial direction. In the nozzle device of the molding machine,
The needle is advanced by the moving driving device, and the front end face of the closing shaft fitted into the ejection port of the nozzle is moved from the opening surface of the ejection port when the moving driving device reaches the forward operation end. Stop inside the closed shaft
The nozzle is closed only by fitting the closing shaft into the injection port without bringing the base portion into contact with the nozzle . The needle may be an inner nozzle having an injection port on the closed shaft.

[0014]

Since the length of the closing shaft and the opening / closing stroke thereof can be shortened, it is possible to eliminate the operation delay and the troubles such as burrs caused by the extrusion of the resin from the injection port. Can be prevented from being cut. Further, since the nozzle is not closed by the contact of the needle with the valve seat, the nozzle or the like is not damaged by the driving pressure of the moving driving device.

[0015]

1 and 2 show an embodiment of a nozzle device of an injection molding machine according to the present invention. The same members and the like as those in FIG. 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

An injection port 11c is formed linearly at the front end of the nozzle 11, and a closed shaft 12 is formed at the front end of the needle 12.
a is provided linearly. Injection port 11c and closed shaft 1
2a has a circular cross section, and its center lines are aligned with each other. The closing shaft 12a is fitted into the injection port 11c to close the injection port 11c. The diameter of the closing shaft 12a is slightly smaller than the diameter of the injection port 11c so that resin leakage does not occur. It is sufficiently shorter than the outlet 11c.

The hydraulic cylinder (moving drive) 15
The needle 12 is advanced, and a part of the closing shaft 12a is fitted into the injection port 11c and stopped when reaching the forward operating end (see FIG. 1), and at the retracting operating end, as shown in FIG. The stroke is determined so that the nozzle can be completely pulled out from the outlet 11c to open the outlet 11c.

Next, the operation of the nozzle device of the injection molding machine according to the present invention having the above configuration will be described. Hydraulic cylinder 1
When the size 5 is reduced, the needle 12 moves forward by the rotation of the lever 14 connected to the rod 15b of the piston 15a by the pin 16, and the closing shaft 12a is fitted into the injection port 11c and closed.

In this case, since the stroke of the hydraulic cylinder 15 is determined as described above, the needle 12
With the hydraulic cylinder 15 reaching the forward operating end, the front end face 12b of the closing shaft 12a is connected to the opening face 11d of the injection port 11c.
The nozzle 11 is closed by only fitting the closing shaft 12a into the injection port 11c without stopping the nozzle 11 with the tapered portion 12c formed at the base of the closing shaft 12a being stopped. Becomes

Therefore, the driving force of the hydraulic cylinder 15 is not applied to the nozzle 11, and damage to the nozzle 11 and the like is prevented. Further, since the opening and closing stroke of the needle 12 is short, there is no time delay, and when the injection port 11c is closed, the injection shaft 11a is closed by the closing shaft 12a.
Since the amount of resin extruded from the resin is small, problems such as burrs can be prevented. Since the closing shaft 12a is short, it does not break due to the resin pressure. The hydraulic cylinder 15 can be another moving drive device using an electromagnet, a motor, or the like.

FIG. 3 shows a second embodiment of the present invention. In this nozzle device, the front portion 11e of the injection port 11c into which the closing shaft 12a is fitted is formed in an outwardly open tapered shape. In the case of this embodiment, the resin remaining in the front portion 11e of the injection port 11c can be easily taken out together with the product and the like. Other structures are the same as those of the nozzle device of FIGS.

FIGS. 4 to 6 show a third embodiment of the nozzle device of the injection molding machine according to the present invention. Note that the same members and the like as those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted.

At the front ends of the outer nozzle 1 and the inner nozzle 2, injection ports 1a and 2a are formed linearly.
At the front end of the needle 3, closing shafts 2 e and 3 a are provided in a straight line. The injection ports 1a, 2a and the closing shafts 2e, 3a are both circular in cross section, and their center lines coincide with each other. The closing shaft 2e is at the outlet 1a, and the closing shaft 3a is at the outlet 2a.
To close them, respectively,
The diameters of the closing shafts 2e, 3a are slightly smaller than the inner diameters of the injection ports 1a, 2a so that resin leakage does not occur, and the lengths are sufficiently shorter than the injection ports 1a, 2a. The inner nozzle 2 functions as a needle with respect to the outer nozzle 1.

The hydraulic cylinder (moving drive device) 26
When the inner nozzle 2 is advanced, a part of the closing shaft 2e is fitted into the injection port 1a and stopped when reaching the forward operating end (see FIGS. 4 and 5), and at the retracted operating end as shown in FIG. ,
The stroke of the closing shaft 2e is determined so that the closing shaft 2e can be completely pulled out from the injection port 1a to open the injection port 1a.

Similarly, the other hydraulic cylinder (moving drive device) 27 advances the needle 3 and stops a part of the closing shaft 3a by fitting it into the injection port 2a when the needle 3 reaches the forward operating end. 4 and FIG. 6), and at the retreat operating end, as shown in FIG. 5, the stroke is determined so that the closing shaft 3a can be completely pulled out from the injection port 2a to open the injection port 2a. I have.

In the nozzle device of this embodiment, when the hydraulic cylinders 26 and 27 are extended, the inner nozzle 2 and the needle 3 advance, and the closing shafts 2e and 3a are connected to the injection ports 1a and 2a.
a and closed. In this case, the strokes and the like of the hydraulic cylinders 26 and 27 are determined as described above, just like the nozzle device of the first embodiment, so that the inner nozzle 2 and the needle 3 move the hydraulic cylinders 26 and 27 forward. When reaching the ends, the front end faces 2f of the closed shafts 2e, 3a
3c is positioned inside the opening surfaces 1e, 2g of the injection ports 1a, 2a and stopped, and the tapered portions 2h, 3d formed at the roots of the closing shafts 2e, 3a are brought into contact with the nozzles 1, 2. And the closed shafts 2e,
The nozzles 1 and 2 are closed only by the fitting of 3a.

Therefore, in this embodiment, the same effects as those of the nozzle device of the first embodiment can be obtained. Note that the configuration of FIG. 3 can be introduced into this nozzle device. Further, the number of fitting stages of the nozzles 1 and 2 can be three or more. Also in this case, as described above, the inner nozzle functions as a needle with respect to the nozzle outside the nozzle. In the case of a nozzle device having a multi-stage structure, if necessary, for example, the closed shaft 3a may extend over the entire length of the injection port 2a.
All injection ports 1
The components a and 2a and the closed shafts 2e and 3a may not be included in the configuration of the present invention.

[0028]

As described above, the nozzle device of the injection molding machine according to the present invention comprises a nozzle having a linear injection port at the front end, which is inserted into the injection port and closes the injection port. A needle formed in the front end of a closed shaft of a shape is inserted concentrically with the nozzle and movably in the axial direction,
In the nozzle device of an injection molding machine, wherein the needle is provided with a movement drive device for moving the needle in the axial direction, the needle is advanced by the movement drive device and fitted into an injection port of the nozzle. The front end face of the closed shaft is positioned inside the opening face of the injection port in a state where the moving drive device has reached the forward operating end, and stopped and closed.
Since the nozzle is closed only by fitting the closing shaft into the injection port without bringing the base of the shaft into contact with the nozzle, the length of the closing shaft and the opening / closing stroke can be shortened. Therefore, there is no trouble such as operation delay and burrs, and the nozzle and the needle are not damaged by the driving force of the moving driving device or the resin pressure.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a nozzle device of an injection molding machine according to an embodiment of the present invention in a closed state.

FIG. 2 is also a sectional view of an open state.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a sectional view showing a retracted state of a needle of the nozzle device of FIG. 4;

FIG. 6 is a cross-sectional view showing a retracted state of the inner nozzle.

FIG. 7 is a sectional view showing a nozzle device of a conventional injection molding machine.

FIG. 8 is a sectional view of another conventional nozzle device.

[Explanation of symbols]

Reference Signs List 1 outer nozzle 1a emission port 1e opening surface 2 inner nozzle (needle) 2a emission port 2e closing shaft 2f front end surface 2g opening surface 3 needle 3a closing shaft 3c front end surface 11 nozzle 11c emission opening 11d opening surface 12 needle 12a closing shaft 12b front end Surface 15, 26, 27 Hydraulic cylinder (moving drive)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-286819 (JP, A) JP-A-7-156202 (JP, A) JP-A-57-163543 (JP, A) JP-A-4- 84654 (JP, A) JP-A-60-212315 (JP, A) JP-A-63-161811 (JP, U) JP-A-59-160216 (JP, U) JP-A-4-113918 (JP, U) JP-B-55-45374 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 45/00-45/24

Claims (2)

(57) [Claims] 1. A needle having a linear closing shaft formed at the front end of a nozzle having a linear injection port at a front end and fitted into the injection port to close the injection port, the nozzle being concentric with the nozzle. A nozzle device of an injection molding machine, which is inserted movably in the axial direction and the needle is provided with a driving device for moving the needle in the axial direction, wherein the needle is moved forward by the driving device for moving. the allowed is by the front end surface of the fitting encased occlusion shaft to the injection port of the nozzle, moving drive device by positioning inside the opening of the injection port in a state of reaching the forward working end stops, and closed Axial
A nozzle device for an injection molding machine, wherein the nozzle is closed only by fitting a closing shaft into an injection port without bringing a root portion into contact with the nozzle. 2. The nozzle device of an injection molding machine according to claim 1, wherein the needle is an inner nozzle having an injection port on a closed shaft.